The castle was founded in a strategic position, on a site settled by Muslim forces during the Iberian occupation, referred to as al-Madan (which means gold mine or silver mine), suggesting that the site was built on mineral extraction in the region or epoch, and referred to in the Geografia Nubiense of Muhammad al-Idrisi (dating to the 12th century.

[1] During the succession crisis of 1383-1385, when the city of Lisbon was under siege (1384), Almada was encircled by forces loyal to Castile, by Condestável D. Nuno Álvares Pereira who was unsuccessful in liberating the region.

[1] During the context of the Portuguese Restoration War (1640-1668), in the reign of King D. Afonso VI (1656-1683) the town was defended by the old castle, and was rebuilt in order to maintain the defense of Lisbon, resulting in the construction of a line of bastions.

[1] It was decommissioned in 1825, and Lieutenant Fulgêncio Gomes dos Santos Vale received orders to collect all the arms material onsite, and transfer it the military arsenal in Lisbon.

[1] He failed in this attempt, with his bomb falling in the town square (today Almada Velha), causing the death of three people and injuring many onlookers, including children flying kites in the vicinity.

[1] Following 1976 its installations were occupied by the forces of the GNR Guarda Nacional Republicana (Republican National Guard), when the building was reconstructed for this purpose.